Aircraft construction



Sept. 27, 1932. G. BETTLE 1,879,046

AIRCRAFT CONSTRUC TIO N Filed Jan. 28, 1950 I N V EN TOR. G mscoM BET TLE.

A TTORNE Y.

'GRISCOM. BEETLE, F GLADW YN', PENNSYLVANIA, ASSIGN'OR T0 EDWARD G. BUDD MANUFACTURING 60., 0F PHILADELPHIA, PENNSYLVANIA, A CORPORATION 015 EENNSYLVANIA r a JD CONSTRUCTION The monocoque aircraft body of my invention has been evolved by me in an endeavor to lighten and strengthen the construction of such bodies especially as covered with a skins transversely of corrugated cross section. Such bodies have heretofore been pro-" duced transversely of corrugated cross sectlon around the ent re perimeter of the transverse cross section and with corrugations exno tending the full length of the body. The corrugations longitudinally stiffen the body to such an extent that in -a number of these bodies the longitudinally extending corrugations of the covering of the body are wholl relied upon to attain the longitudinal sti ness sof the body, longitudinally extending stringers and longrons being eliminated altogether. The general transverse cross sectional form is maintained by transverse bulkheads of suitable construction disposed at intervals longitudinally of the body. The

corrugated covering or skin is connected, to

these bulkheads preferably at the bottoms of the corrugations in some forms known to me.

I attain the objects of my invention by.

constructing the opposite sides of, the skin or covering, as distinguished from the top and bottom of such covering, of smooth transverse cross section as distinguished from corrugated cross section. By smooth I mean free from transverse corrugations of such cross section, or, conforming to the smooth perimeter of the transversebulkheads. The surface free from transverse corrugations is of less extent than the surface provlded with such corrugations. It is, therefore, of less weight per unit length of the perimeter of cross section. .Moreover, the provision of the smooth cross sections on the opposite sides.

of the body enables the material of the covering the more immediately and efliciently to bear tension loads imposed in the opposite sides of thebody. When these too are of corrugated cross section, by reason of the susceptibility to elongation of transverse 7 cross sections intermediate the bulkheads and a tendency toward distortion of the corrugations in these intermediate regions, when any strain in the general direction of the'plane of symmetry is imposed on the opposite sides,

there is opportunity for relative movement of parts and a slight time lag before the material develops its full resistance to such tension. In the smooth cross section the material is decidedly'more immediately placed in full tension and in smooth cross sections of substantially plane form the material is instantly placed in tension. More-economical and eficient use of material results.

In the accompanying drawing I show' the best form of my invention now known to me:

Figure 1 shows it in perspective, in three quarters side view from the front, and with its fore end in transverse cross section, while F igure 2 constitutes afsegmental transverse cross section on an enlarged scale of the corrugated portion of the body.

Figure 3 is a transverse cross section at or near the tail of the body.

Flgure 41s a dlagram showing dlagrammatically the substantially constant radius,

- The web 11 is lightened by the provision of holes 13. The bulkhead at largeis in the formof a ring of this cross section.

The skin comprises the transversely corrugated top and bottom portions 14 and 15 and the transversely smooth side portions 16 and in planes in general diagonal to the vertical plane of symmetry of the body,'and passing through the axis of the body.

The corrugated and smooth cross sections 14 to 17 are joined to each other in these lines 18. The transversely corrugated covering 14 and 15 is joined to the bulkheads in the bottoms of the corrugations as shown especially well in Fig. 2. Corrugations are shown as concave throughout their longitudinal extent and the fastening means is shown as rivets. It may be spot welds or other means.

covering lying substantially in planes diagonal to the body and passing through its axis. In testimony whereof he hereunto aifixes The smooth cross section sides 17 are likewise hissignature.

joined to the bulkheads by riveting or welding, riveting being shown in Fig. 1.

In the embodiment shown the opposite sides of the covering 16 and 17 approach approximately a plane form, the bulkheads 10 being somewhat flattened at the sides. The forces of tension set up in them are thereafter substantially instantly developed in the material at maximum activity and efliciency of the material. They are not necessarily, however, of plane form or approximately of plane form, but may be of a curved surface in harmonious form to the general transverse and longitudinal curvature of the top and bottom coverings 1 1 and 15 of corrugated transverse cross section. This is illustrated by the curvature of the dotted lines 19. While this form does not realize-my invention to the full as in the instance of the smooth sides shown in full lines as 16 and 17, it nevertheless realizes it in part.

That the invention realizes in full the advantages which I have set forth should be apparent. In addition, the aerodynamic characteristics of the body by reason of the lesser resistance to forward movement incident to the smooth sides are improved. Sometimes the corrugations might lie parallel to the air stream. At other times they might be at an angle. Particularly in cases where the corrugations might be at an angle, the smooth sides offer less resistance.

My invention is susceptible of use in other structures beside aircraft and should be protected to me by the annexed claims in whatsoever situation use is found for it. Being susceptible of this and other uses and yet other modifications than those indicated, its scope is to be interpreted in view of the prior art rather than by the circumstantial terminology of the annexed claims.

lVhat I claim as new and useful and desire to protect by Letters Patent is 1. A tapered aircraft body having top and bottom coverings corrugated in transverse cross section and side coverings smooth in transverse cross section, which coverings are joined together substantially in longitudinal planes diagonal to the longitudinally extending central vertical plane of the body and passing through the axis of the body.

2. An aircraft body of monocoque construction comprising separated frame members in spaced transverse planes and longitudinally extending skin covering said frame members and transversely of corrugated and convexly rounded cross section top and bottom and smooth and relatively flat cross section on the sides, the lines of joinder between the corrugated and smooth portions of the GRISCOM BETTLE. 

